The first PC has an add-in graphics card over the onboard graphics.
The first PC has an Athlon 64 over an Athlon XP.
The first PC has PC3200 memory instead of PC2700.
The first PC has a DVD+/-RW drive instead of + only.
The first PC has a CD-ROM drive for Drive-to-Drive copying.
The first PC has a SATA drive instead of IDE.
The first PC has Farcry.
The only good things I can see for the HP is that it is a dual-layer DVD burner (but the discs cost a lot of $$) and it has a bigger harddrive.
Unless of course you count MS Works as a plus...